The effectiveness of physical activity interventions in improving higher education students’ mental health: A systematic review

Abstract Traditional interventions aiming to improve students’ mental health and quality of life include meditation or canine therapy. The development of physical activity-related interventions has increased over the past decade. We aimed to review all studies using physical activity for improving the mental health and quality of life in higher education students whilst describing the interventions, measurements and effectiveness. A systematic search of six electronic databases including: ProQuest, MEDLINE, Embase, CINAHL, SPORTDiscus and CENTRAL, was conducted following PRISMA guidelines. Randomized or non-randomized controlled trial physical activity-related interventions involving higher education students aiming to improve their mental health and quality of life were included. Searches yielded 58 articles with interventions involving martial arts, sport, mind–body exercises and anaerobic exercises. Psychological measures varied across studies including the State Trait Anxiety Inventory, Beck Depression Inventory and the Perceived Stress Scale. Over half of the studies included in this review (n = 36) were effective in improving students’ mental health or quality of life. Findings from our review suggest that interventions aiming to be effective in improving students’ mental health quality of life should aim to deliver moderate-vigorous intensity exercises such as dance or Pilates. This systematic review was based on a published protocol in PROSPERO (registration number: CRD42022325975).


BACKGROUND
The benefits associated with being physically active are well-recognized.Regular participation in physical activity (PA) has been associated with positive longterm influences on obesity, cardiovascular heart disease and type 2 diabetes mellitus in adults (Reiner et al., 2013) and is also associated with lower depressive symptoms, anxiety and stress (UK Government, 2019).Interest in the role of PA on mental health and quality of life (QoL) has increased over the past few years due to the Coronavirus Disease-19 (COVID-19) outbreak (Ozdemir et al., 2020).Nevertheless, the known improvements in outcomes relating to mental health (e.g.depression, anxiety, stress, etc.) and QoL (e.g.personal health (physical, mental and spiritual), relationships, education status, work environment, social status, wealth, etc.) through PA have been observed for decades (Saxena et al., 2005;Acree et al., 2006;Bize et al., 2007;Farris and Abrantes, 2020).To gain the health benefits associated with being physically active, the World Health Organization (WHO) provide PA guidelines for adults aged 18-64 years (World Health Organization, n.d.).These outline that adults should participate in at least 150-300 min of moderate-intensity aerobic PA or at least 75-150 min of vigorous-intensity activity weekly.The WHO also recommends that adults should also participate in muscle-strengthening activities and limit sedentary time.
Higher education (HE) students are largely recognized as inactive (Pengpid et al., 2015), with a decline observed in activity from high school into HE (Bray and Born, 2004).College students indicate that the quality of on-campus facilities, need for social support to encourage exercise and lack of time and motivation are barriers to PA (LaCaille et al., 2011).
In HE students, meeting PA guidelines has been associated with improved physical health and mental health (Murphy et al., 2018), and less academic stress compared to students who are inactive (Gasiūnienė and Miežienė, 2021).It is unsurprising that a recent systematic review noted a positive relationship between PA and academic performance in HE students across the USA, France and China (Wunsch et al., 2021).Alarmingly, findings from a study in 23 low-, middleand high-income countries found that 41.4% of university students were physically inactive (Pengpid et al., 2015) ranging from 21.9% in Kyrgyzstan to 80.6% in Pakistan.Whilst the benefits of PA for HE students are clear in relation to health and academic performance, globally these students are inactive.
HE is a time of increased autonomy and selfdevelopment for students, however, poor diet and PA behaviours can develop, with research highlighting failings of HE organizations in the promotion of PA for their students (Keating et al., 2005).Additionally, many HE students face issues with their mental health and QoL ranging from anxiety to alcohol use disorders (Castillo and Schwartz, 2013).HE institutions are promising settings to promote PA opportunities, as the target population can be easily reached, whereby interventions to improve the mental health of HE students can be easily administered (Martinez et al., 2016).In turn, the improvement of mental health through participation in PA can have positive effects on academic performance (Al-Drees et al., 2016).To attempt to enhance health-related behaviours in HE students, previous studies have relied on psychological-based therapies to remedy HE student's mental health problems (Reiner et al., 2013;Binfet, 2017).Findings from a systematic review and meta-analysis exploring the use of cognitive behavioural therapies including mindfulness programmes for the treatment of stress, depression and anxiety in students found a medium effect size for stress and anxiety, but a small effect for depression (González-Valero et al., 2019).Studies examining the effects of canine therapy on university students' stress have shown that spending time with therapy canines significantly reduces stress (Binfet, 2017;Binfet et al., 2018).Over the past decade, there has been an increase in interventions employing PA or exercise to improve HE student's mental health and QoL.Although a review has been conducted examining the effectiveness of interventions targeting PA, nutrition and healthy weight for HE students (Plotnikoff et al., 2015), this current review is the first to investigate the effectiveness of PA-related interventions in improving the QoL and mental health outcomes in HE students.

OBJECTIVE
The objective of this article is to systematically review the evidence available regarding the impact of PA-related interventions to improve mental health and QoL outcomes in HE students to determine the following research questions:

METHODS
This systematic review was based on a published protocol in PROSPERO-International prospective register of systematic reviews (registration number: CRD42022325975) following PRISMA guidelines (Page et al., 2021).

Type of interventions
Interventions deemed eligible for inclusion had to include a PA or movement-based component, aiming to improve student's mental health and/or QoL.Interventions of all lengths and mode of delivery (e.g.online, on-campus, etc.) were included.

Type of studies
Original quantitative studies including RCTs and non-RCTs were eligible for inclusion.Cross-sectional studies, systematic reviews and meta-analyses were not included.

Type of outcome
This review focuses on the psychological effects of the intervention received relating to the mental health and/ or QoL of HE students.

Data extraction
The search results were exported to Zotero® to eliminate duplicates.Titles were screened and eligible studies were downloaded onto excel, reviewed for any remaining duplicates missed by Zotero (S.D.) and the abstracts were manually screened by two researchers independently (S.D. and M.K.).If there was any discrepancy, a third investigator (K.P.) was called to reach a mutual consensus amongst the research team.The full texts of these articles were retrieved.Subsequently, the reference lists of selected studies were reviewed (S.D.) to identify additional relevant studies.From all the eligible full-texts, data were extracted by three researchers (S.D., M.K., K.P.).The following summary data were considered: country, study design, sample size, gender, age (range and mean (standard deviation: SD)), diagnoses, intervention characteristics, analysis, outcomes and effectiveness of intervention.

Data analysis
Across all study designs the purpose of the study, specific population of interest (within HE students); type, duration, and follow-up period of the intervention; and specific mental health measures are described with consideration to key attributes of robustness and generalisability.

Risk of bias (ROB)
ROB was assessed, whereby three reviewers (S.D., M.K., K.P.) reviewed all included studies.Thereafter, the reviewers discussed the assessment of the included studies to come to a final agreement of the assessment of each paper.ROB for RCTs was assessed using the revised version 2 of the Cochrane ROB for randomized trials (RoB 2) (Sterne et al., 2019).The ROB of all included non-RCTs was assessed using the ROBINS-I tool (Sterne et al., 2016).This tool provides a systematic way to organize and present the available evidence relating to ROB, and by signalling questions, answers can help identify areas of concern regarding ROB.
Similarly, to the RoB 2 tool, outcomes for each individual domain are generated alongside an overall ROB outcome.

Characteristics of included studies
Characteristics of the included studies are summarized in Table 1.Of the 58 included studies, most (n = 38, 66%) were RCTs.Furthermore, most studies (n = 17)      Intervention dose is given as the minutes per activity session, number of sessions per week and number of weeks of the intervention.This was used to estimate an approximate total length of intervention in minutes.Note these numbers are indicative only as some study designs had variable length sessions and sessions per week; or increased duration/intensity over the length of the study.Abbreviation NSL = no set length.
5 Indicated if the study found a statistically significant difference on one or more psychological outcomes between comparator groups; if there was no comparator group then this indicates effective pre-post comparison as indicated.Psychological measurements with estimated effect sizes for effective RCT studies are listed on a separate table. 6 Description of study indicates it was a randomized controlled trial, however authors describe as quasi-experimental.Due to ambiguity, it is listed with the non-RCT studies.
Table 1.Continued were from the USA followed by 11 in China, and 6 in Canada.Four studies were from Iran, and three studies were included from both Germany and Spain.Two studies came from Japan, Turkey and the Netherlands, and the remaining countries were associated with one study each; Australia, Belgium, India, Korea, Malaysia, Norway, Taiwan and the UK (see Table 1).Only one RCT study reported the use of behaviour change theory (Mailey et al., 2010), which was social cognitive theory.

Incentive to participate
Only 13 (22%) studies outlined small incentives to participate which included the award of additional course credits, money, prize draws (e.g.amazon voucher) and free yoga classes (see Table 1).

Diagnoses, psychological outcomes and measurements
Eighteen studies (31%) required participants to have a psychological diagnosis or experience including being referred by the on-campus mental health team, experiencing anxiety, experiencing moderate depression, or having attention deficit hyperactivity disorder (ADHD).Other studies had inclusion criteria based on activity levels or previous exercise experience (n = 16, 28%) and the remainder (n = 24, 41%) had no specific inclusion criteria other than being students, although recruitment may have been restricted to sub-groups of students (such as course enrolment or dormitories).
Most of the studies (n = 48, 83%) reported psychological outcomes as their primary outcome, including perceived stress, depression, state anxiety and QoL.
Five of these studies did not have a comparator so the effectiveness relates only to changes over time (prepost) and not between groups.Where an intervention was found to be effective the effect sizes were typically medium to large, in either an adjusted repeated measures analysis or a less robust sequence of paired Of these studies, 25 were found to be effective (Crocker and Grozelle, 1991;Bass et al., 2002;Caldwell et al., 2009;Akandere and Demir, 2011;Hemat-Far et al., 2012;Gallego et al., 2014;de Vries et al., 2016de Vries et al., , 2018;;von Haaren et al., 2016;Huang et al., 2017;López-Rodríguez et al., 2017;Faro et al., 2019;Ezati et al., 2020;Herbert et al., 2020;Muir et al., 2020;Wan Yunus et al., 2020;deJonge et al., 2021;Fukui et al., 2021;Saltan and Ankaralı, 2021;Xiao et al., 2021;Ji et al., 2022;Zhao et al., 2022;Danielsen et al., 2023;Gurung et al., 2023;Sandra et al., 2023).Four studies did not find significant intervention effects.Two of these studies compared an aerobic intervention with a yoga intervention (     expressive writing (Marschin and Herbert, 2021); and 1 study used cycling/running interventions (Brown et al., 1993).Notably the cycling/running intervention did not include general student populations, rather it recruited physically challenged students, enrolled in an adaptive physical education class for a single 20-min session.

High-intensity interventions.
HIIT interventions (n = 6) included three RCTs (Eather et al., 2019;Philippot et al., 2022;Zhu et al., 2023), two of which were pilot (Philippot et al., 2022;Zhu et al., 2023) and three non-RCTs (Martínez-Díaz and Carrasco, 2021;La Count et al., 2022), one of which was a pilot (Martínez-Díaz and Carrasco, 2021).Only the RCT pilot intervention (Philippot et al., 2022) showed effectiveness for HIIT interventions.The oldest study in this group describes a procedure of sequential maximal exercises similar to HIIT, although published prior to the popularization of the term (O'Connor et al., 1995).They found that this training increased anxiety immediately post-training for low-fitness students, although anxiety returned to baseline at follow-up.This study also included maximal treadmill exercises with both highly trained runners and physically fit students who also did not find the sessions effective in reducing anxiety.

Mind-body PA interventions.
There were 19 studies which used mind-body interventions (Albracht-Schulte and Robert-McComb, 2018;Caldwell et al., 2009;Dinani et al., 2019;Forseth et al., 2022;Gao et al., 2022;Kim et al., 2013;Kim et al., 2004;Li et al., 2015Li et al., , 2022;;Salehian et al., 2021;Schmalzl et al., 2018;Strehli et al., 2023;Sun et al., 2023;Tong et al., 2021;Wang et al., 2004;Xiao and Zheng, 2022;Zhang et al., 2023a;Zheng et al., 2015;Zhang and Jiang, 2023) including various forms of yoga, Tai-Chi, Qigong (including Baduanjin), Kouk Sun Do, and meridian exercise, where studies (Caldwell et al., 2009;Tong et al., 2021;Xiao et al., 2021) were also included in the previous section as they were comparisons between mind-body interventions and MVIPA interventions.Overall, these studies provide mixed evidence of effectiveness with only 6 out of 12 RCTs finding at least one significant improvement in a mental health or QOL measure against the comparator (see Supplementary File S1: SF1).Eight studies compared with the usual routine, and one each for quiet rest, health education or ujjayi breath.Most of these interventions were lengthy with typically 60-min sessions 2-5 times per week for 8-12 weeks.There were seven non-RCTs, with five claiming the intervention was effective, however, three of these were pilot studies with no comparator.Tong and colleagues (2021) found yoga to be superior to aerobic-style exercises however students self-selected into groups and the effect was primarily considered to be through increased mindfulness rather than a direct measure of mental health or QOL.
Two studies which did not find Tai Chi or Baduanjin to be effective were from the same research group and rigorously designed with similar published protocols (Zheng et al., 2013(Zheng et al., , 2014)).They included long interventions (each 12 weeks), the largest sample sizes (approximately 200 participants each) and intention to treat analyses.In both cases, the authors posit that differences with the control group may have been difficult to detect as there were no limits on what activities the control group may have been involved with outside of the trial.The background of the participants may be an important consideration as they were students of traditional Chinese medicine, whereas the three trials which were found to be effective involved nursing (Kim et al., 2004;Dinani et al., 2019) or general university students (Xiao et al., 2021).These studies had smaller sample sizes (approximately 30 students per group) and ran for 6, 8 and 12 weeks, respectively.There was also a pilot trial with a small sample size of 18 students which found evidence for the effectiveness of Kouk Sun Do in improving the mental health of students (Kim et al., 2013).The non-RCT studies which found some evidence for the effectiveness of Tai Chi included a pilot trial with no comparator (Wang et al., 2004) and, an Iranian study looking specifically at Corona-disease anxiety which did not find Tai Chi effective in comparison with cognitive-spiritual therapy (Salehian et al., 2021) but was more effective than the control (receiving no intervention).Overall, the evidence is mixed and suggests that mind-body exercises may be effective for improving students' mental health, however, this may depend on the background of students and which activities they already usually participate in.

Miscellaneous interventions.
There were seven miscellaneous studies including five RCTs (Mailey et al., 2010;Sharp and Caperchione, 2016;Zimmermann and Mangelsdorf, 2020;Chawla et al., 2022;Mota et al., 2023) and two non-RCTs (Tayama et al., 2012;Koschel et al., 2017).None of these studies found the interventions to significantly improve HE students' mental health and/or QoL.There were three pedometer-based interventions (Mailey et al., 2010;Tayama et al., 2012;Sharp and Caperchione, 2016) which did not specify a number of steps or intervention lengths to participants.It could be argued these are not truly movement-based interventions, but rather tracking-based interventions (with the aim that tracking might increase movement).Similarly, Mota and colleagues (2023) trialled a mobile health app as an intervention which included exercise videos but did not specify the amount of exercise to complete.Another two studies were considered in this category as they involved only a single session or event.One compared a single 20-min creative movement versus art (Zimmermann and Mangelsdorf, 2020) and whilst both groups improved over time there was no difference between the groups.The other allowed students to choose activities within a 3-day on-campus event and whilst it is not called a pilot or feasibility trial, the sample size was 15 students (Koschel et al., 2017).The final study compared squat exercises with and without whole-body vibration and both groups improved in the domains of depression, anxiety and stress (Chawla et al., 2022).In this case, the intervention is the addition of the whole-body vibration in conjunction with the exercises, which was not effective.

Assessment of ROB
ROB assessment for included RCT studies is summarized (see Supplementary File S2: SF2) and outlined in relation to each RCT study (see Supplementary File S3: SF3).Most of the RCT studies included (n = 22; 58%) scored low in overall ROB, with a further 10 having an unclear ROB, and 6 having high ROB.It is important however to consider that it not possible to blind participants to these types of interventions.Assessment of ROB for included non-RCT studies is summarized (see Supplementary File S4: SF4) and outlined in relation to each non-RCT study (see Supplementary File S5: SF5).Similarly to the RCT studies, overall, most of the non-RCTs reported low ROB (n = 12; 60%), whereas five were unclear and the remaining three had a high ROB.

DISCUSSION
This systematic review suggests that exercise interventions, which are MVIPA, can positively impact the mental health and/or QoL of HE students.Interventions include Pilates, aerobic exercises, basketball, weight, resistance and gym training, dance, exercise games and home workouts and running.Mixed results were observed for mind-body interventions in improving the mental health and/or QoL of HE students.However, there was substantial variability between studies in relation to the context, sample size, intervention duration and outcomes.Interventions involving HIIT were not found to be effective, except for a single pilot study.However, there were only three studies (Eather et al., 2019;Philippot et al., 2022;Zhu et al., 2023) trialling HIIT in a similar design to other movement-based interventions (in terms of duration) so this area needs further research.Interventions which gave participants access to tracking their physical activity (such as pedometers or mobile app) which did not have a specific session length or duration were not effective (Mailey et al., 2010;Tayama et al., 2012;Sharp and Caperchione, 2016;Mota et al., 2023).Overall, there is substantial variety in the type, duration and measurement of PA interventions, but there is evidence that these can improve aspects of mental health with an appropriate program.

STRENGTHS AND LIMITATIONS OF PRIMARY RESEARCH
PA trials rely upon the participants volunteering to participate and in turn, conclusions about effectiveness cannot be drawn for students in general as they may not have the internal motivation to initiate or maintain participation in such activities.One study (Ezati et al., 2020) used a block allocation of students based on dormitories and still found the intervention effective.Further studies of this type could offer insights into general adherence and attrition; however, it may be more challenging in settings where students are not 'captive' based on residence.This is discussed further in recommendations.Additionally, most studies fail to detail information surrounding participants' regular activities and the activities of the control groups after not being assigned to the intervention arm.
Many of the RCT studies included in this review use validated instruments to measure psychological outcomes (Table 2), including the STAI, PSS and BDI.Of the studies included, many included interventions administered over several weeks (≥20 weeks).This is an individual strength within studies only, as such a wide array of instruments are used making any comparisons between studies problematic.Additionally, many studies used multiple measures and sequences of paired t-tests, inflating the type 1 error rate (i.e.false positives).Assessment of multiple psychological outcome measures also raises questions surrounding the accuracy of the results as participants may experience survey fatigue.

STRENGTH AND LIMITATIONS OF THIS SYSTEMATIC REVIEW
A strength of this systematic review is the inclusion of exhaustive searches for relevant peer-reviewed journal articles in six library databases.Although searches were restricted to articles written in the English language only, research findings from a range of different countries where English is not the first language are included.The majority of included studies (n = 34 studies, 58.6%) had low ROB.Only nine studies (15.5%) were found to have high ROB.
This review has several limitations.First, it was not feasible to conduct meta-analyses due to heterogeneity in study designs, interventions, outcome measures and types of analysis conducted.Second, variations in the length and intensity of interventions limits direct comparison across all included studies.Lastly, this systematic review includes only peer-reviewed journal articles, so publication bias may be a potential limitation of the findings since studies with negative or inconclusive findings may be less likely to have been published (DeVito and Goldacre, 2019).

RECOMMENDATIONS FOR FUTURE PRACTICE
This review supports the ongoing evaluation of MVIPA interventions for the mental health and wellbeing of HE students.There is evidence that these can be effective for students who are interested in participating.Given the numerous forms of PA, it is valuable to have ongoing research on different interventions.However, it would be helpful to use standardized instruments (e.g.STAI, BDI, PSS and DASS) so that future meta-analysis is possible, and to continue to run trials which continue for several weeks.There is currently only limited evidence of the effectiveness of PA as a general health-promotion activity aimed at all students for mental health.Further research is needed on feasibility, acceptability and adherence within this framework.One study used a block allocation of dormitories (Ezati et al., 2020) and the intervention group did have slightly higher non-compliance than the control group (i.e. 5 vs 1 students, respectively) but the overall sample size is still relatively low (i.e.67 students).Additionally, two studies used entire classes as experimental groups (Marschin and Herbert, 2021;Tong et al., 2021), however, these were fitness and psychology classes, respectively, and may not be directly applicable to students in non-health-related fields.From a health-promotion lens, it would be valuable to understand which activities would encourage participation and adherence, and if students who are experiencing symptoms of stress, anxiety and depression can be encouraged to participate.
Most studies found a gender bias in participation (i.e.greater proportion of females than males).This limitation is not unusual.A systematic review on the prevalence of mental health problems in undergraduate students found that more than half had greater than 60% female participation (Sheldon et al., 2021).The only intervention in this review which skewed to a greater proportion of males (without being exclusively male) included basketball as an intervention (Xiao et al., 2021).A systematic review of PA interventions for physical health also found that more than half of the studies included predominantly female participants (Plotnikoff et al., 2015), and that overall interest in the interventions was relatively low.It is possible that a PA intervention explicitly aimed at improving mental health rather than physical health may attract wider and more diverse participation.It would also be of interest to hear student perspectives on the 'attractiveness' of programs which are promoted for reducing stress and anxiety, rather than reducing weight.Loneliness was only considered explicitly in one of the studies in this review (Xiao et al., 2021), however, this is also a growing concern for HE students in wider research (Bernardon et al., 2011;Diehl et al., 2018).
Pragmatic trials which report initial interest, engagement throughout the semester and the student perspective would complement the existing research on efficacy.It is unlikely that a single PA intervention would be appealing to all students, however, a range of activities which could include a social element, may influence uptake and regular attendance.In this review, only one study offered a range of activities (Koschel et al., 2017).Although it did not find that the program was effective in reducing stress on quantitative measures before exams, it was only a 3-day intervention with a small sample size and the qualitative feedback found that all students in the intervention group felt it had reduced stress.This approach may provide a framework for a larger and longer program.

CONCLUSION
This systematic review offers the first detailed synthesis on PA and exercise-specific interventions targeted at improving the mental health and wellbeing of HE students.The evidence suggests that these interventions can positively impact the mental health and QoL of HE students.Evidence shows those interventions which include MVIPA to be the most effective, including aerobics, dance, basketball and running.Mind-body exercises including yoga, Tai Chi and Qigong may also be effective depending on context however this evidence is mixed.HIIT and pedometer/ tracking interventions were not effective in improving psychological outcomes in HE students.Implemented long-term and widely across HE institutions, MVIPA interventions may improve mental health in HE students.

Contribution to Health Promotion
The reported effectiveness of interventions is described for RCT and non-RCT studies, with the comparators also of interest for the RCTs.The theoretical frameworks underpinning interventions are also described.Due to the heterogeneity of study designs, interventions and outcome measures a meta-analysis was not possible.

Table 1 :
Summary details of included studies

Table 1 .
ContinuedPhysical activity interventions in improving higher education students' mental health 7

Table 1 .
Continued to indicate the participants did not need any experience or regular activity; Expert is used to indicate that participants had significant experience in a relevant activity; Medical (phys & psych) indicates that there were medical exclusions for physical and psychological indications, these varied between studies.
1 Number of participants in the analysis and the median group size as there are slight variations between groups in most studies.2Meanageand standard deviations were pooled across groups statistics if overall demographics were not given; NS = not stated; age range (min-max) is stated in lieu of other summary statistics where available.3Noviceis used

Table 2
(Akandere and Demir, 2011;Bassate-Trait Anxiety Inventory (STAI) and Beck Depression Inventory (BDI).Intervention effectivenessInterventions were effective in 36 studies (62%) for improving at least one measure of mental health or QOL in HE students(Akandere and Demir, 2011;Bass

Table 2 :
Summary of psychological instruments used and the language adaptation if known, if no language is stated it is assumed to be in English based on study location

Table 2 .
ContinuedPhysical activity interventions in improving higher education students' mental health